CVE-2026-23743: Discourse allows permalinks to restricted resources to leak resource slugs to unauthorized users
Discourse is an open source discussion platform. In versions prior to 3.5.4, 2025.11.2, 2025.12.1, and 2026.1.0, permalinks pointing to access-restricted resources (private topics, categories, posts, or hidden tags) were redirecting users to URLs containing the resource slug, even when the user didn't have access to view the resource. This leaked potentially sensitive information (e.g., private topic titles) via the redirect Location header and the 404 page's search box. This issue is patched in versions 3.5.4, 2025.11.2, 2025.12.1, and 2026.1.0. No known workarounds are available.
Affected Software
Event History
Frequently Asked Questions
What is the severity of CVE-2026-23743?
CVE-2026-23743 is considered a medium severity vulnerability impacting access control.
How do I fix CVE-2026-23743?
To fix CVE-2026-23743, upgrade your Discourse installation to version 3.5.4 or later versions 2025.11.2, 2025.12.1, or 2026.1.0.
Who is impacted by CVE-2026-23743?
Users with Discourse versions earlier than 3.5.4, 2025.11.2, 2025.12.1, or 2026.1.0 are vulnerable to CVE-2026-23743.
What are the consequences of CVE-2026-23743?
CVE-2026-23743 may allow unauthorized users to access restricted resources through permalinks.
Is there a workaround for CVE-2026-23743 before updating?
There are no effective workarounds for CVE-2026-23743; updating is the recommended action.